In order to provide effective and cheap distribution of goods, many goods are distributed on pallets, by way of example on so-called EU pallets (800×1200 mm). Yet a continuously increasing need has appeared for also dispatching orders comprising smaller consignments of goods in a correspondingly efficient way. Statistically, it has appeared that many orders for small shops actually consist of consignments of goods often consisting of very few layers or maybe just a single layer of palletised goods.
WO 2000/64790 A1, WO 2008/019691 A1, WO2010097088 A1 disclose apparatuses for handling layers of palletised goods, the apparatuses comprising a vertically displaceable lift head with a horizontal suction face which is adapted in size to a pallet and horizontal suction face consists of a large number of downwards open suction chambers. The suction face is arranged to be moved downwards against the top side of an upper layer of individually or group-wise packed goods on a pallet, where the suction chambers are connected via individual valves with a source of vacuum incorporated in the lift head, and where the apparatuses are intended for interacting with depalletising systems. The valves between the suction chambers and the source of vacuum are designed as ball valves with very light thin-walled valve bodies which are enclosed in the suction chamber by means of lateral projections or by means of a retainer net and which interact with upper round valve openings with spherical valve seats at the bottom if the actual suction chamber is not closed at the bottom by contacting the top side of the goods in an upper pallet layer. In connection with each valve, there are arresting means adapted to prevent the valve balls from shutting off the valves, such that it is ensured hereby that the shutoff valves of the suction face can be forcibly opened, when there is a contact to the goods in the pallet layer, and can be forcibly opened, when there are gaps or openings in the pallet layer. The descriptions of these previous inventions are hereby incorporated in the present application by reference.
In connection with the hitherto common handling of layers of palletised goods, it is known to work with rectilinear lifting and moving of pallet layers, i.e. moving pallet layers mutually between positions on mutually perpendicular pallet ways. Experiments have been made using robot technology for moving palletised layers of goods by means of current suction heads. However, the use of robots results in an entirely different movement pattern which also includes swinging movements of suction heads thus imposing significantly greater demands on the suction ability in order to hold the relatively heavy and possibly open pallet layer in a secure way during swinging movements, where centrifugal force actions occur.
Along the outer sides of the suction face, the lift head comprises squeezing means adapted to exert an inwardly pressure at the outer sides of the goods in at least an uppermost pallet layer. The squeezing means comprises a number of inflatable squeezing pads typically operated by a high pressure blower, by way of example a side duct blower.
A problem with these squeezing means is that goods might be damaged due to a high squeezing pressure and further, the packaging around the goods might be damaged or at least visually damaged. In both situations, the value of the goods will go down.
The object of the invention is to solve the above-mentioned problems.